This invention relates to a stabilized synthetic resin composition containing a special phenolic polymer improved in heat resistance, light resistance, and the like.
It is known that polyethylene, polypropylene, ABS, polyvinyl chloride, and the like are deteriorated, colored, or lowered in mechanical strength by the action of heat and light so as to make these synthetic resins useless. In order to prevent these synthetic resins from such deterioration, various additives have been used alone or as a mixture thereof. Among these additives, phenolic antioxidants have a relatively large stabilizing effect and thus widely been used. But these antioxidants mostly lose their effects in a relatively short time, or rapidly, particularly when the synthetic resins are placed outdoors or in a humid atmosphere. Further, these effects are also undesirably lost during processing of these synthetic resins at high temperatures.
In order to improve these antioxidants in water resistance and volatility, there have been attempts to make molecular weight of these antioxidants higher. For example, U.S. Pat. Nos. 3,004,953; 3,328,489 and 3,996,198 disclose polymers of alkylphenols and dialkenyl benzenes. But when these polymers are used, the water resistance and volatility are improved to some extent but they are insufficient in anti-oxidant action. Further, when a synthetic resin compounded with such a polymer antioxidant is exposed to fluorescent tube illumination, there is a defect in that coloring is remarkable. Therefore, these polymer antioxidants are insufficient in practical utility.